The good way to interrupt somebody is to smile broadly, match their enthusiasm level, and use reflective listening to get them to stop talking without demoralizing them. You say, “Wow! It sounds like that pig farm next to the corporate office smelled horrible!” The candidate nods and says “Yes!” and appreciates your empathy and respect. Then you immediately say, “You were just telling me about launching that direct mail campaign. I’d love to hear what was that like? How well did it go?”